Monday, November 21, 2011

What is a Plugin file?

A Plugin is a component that forms the gateway between a webserver and it's corresponding Application Server. All the requests that comes to the WebServer (eg:- IBM HTTP SERVER) will be routed to WebSphere Application Server with the help of a PLUGIN.

PLUGIN is responsible for filtering and redirecting this requests to the application server and the configuration it uses is called Plugin-cfg.xml. This file basically contains all the information of the WAS destination like the route, server host, cluster information, Virtual Host, Transport Chain settings etc. Correct entries in this file decides the correct passage of requests from IHS server to WAS. So it is extremely important to have the most updated details in this Plugin file. All the features like Load balancing, Clustering heavily depends on the content inside a Plugin-cfg.xml file.

After the deployment of application & WAS environment settings creation, we generate the plugin from WebSphere Console and propogate it to the IHS Server. As a result each request going to IHS, will read this content from plugin-cfg.xml file and route the requests to the WAS.

This is just an introduction to Plugin component, we will discuss detailed analysis of this request flow later in this blog.